If you're an expectant mom, you've no doubt got questions you're dying to get answered, and since your ob/gyn likely doesn't appreciate random calls from freaked out patients at 3 a.m., we got expert answers to 10 of the most common questions about pregnancy.

Why Is My Hair Thicker?

The reason behind your lustrous new locks isn't what you might think. You aren't growing more hair, you're just losing less of it. Pregnancy's high levels of estrogen prolong the "growth phase" of hair follicles, which means they stick around on your head longer before they fall out, says Dr. Frederick. The result? A more massive mane. Not that you're complaining.

Why Do Pregnant Women Develop Food Cravings?

If you've forced hubs to schlep to the market at odd hours for doughnuts or waffle fries, well, we hear you. But don't blame these pregnancy cravings on your baby. A University of Albany study found that the cause behind these hankerings is more likely psychological rather than physical. It's not that your growing fetus is clamouring for more ice cream. It's that you've taken your pregnancy as a carte blanche reason to overindulge as you "eat for two."

Why Am I Suddenly Disgusted By Certain Foods?

Scientists think this occurs because your raging hormones alter the smell and taste receptors in your nose and tongue. But there are upsides to being grossed out by chicken or fish. Research from Cornell University suggests that your food aversions may help you avoid certain toxins, and keep baby safe from whatever harmful things you might ingest.

Why Does Morning Sickness Accompany Some Pregnancies But Not Others?

Why nausea occurs at all during pregnancy is still a mystery unto itself, although most experts blame skyrocketing levels of human chorionic gonadotropin (hCG), a hormone that helps maintain your pregnancy. "These levels can be different in each pregnancy, and therefore morning sickness can be in one pregnancy and not another," says Jessica Shepherd, MD, a professor at the University of Illinois and founder of Her Viewpoint. The good news? Some studies have found that women with excessive morning sickness are more likely to go to term, their babies suffer fewer birth defects and have higher IQs.

Why Are There Dark Spots Popping Up All Over My Body?

If your body is suddenly covered in dark patches, rest assured it's entirely normal. "Estrogen stimulates pigment production in skin cells called your melanocytes," explains Dr. Shepherd. That line down the middle of your stomach even has a name: linea negra. And don't worry, these marks all will disappear once the baby is born and your hormonal makeup returns to normal.

Why Are My Nipples Darker?

In the same way that hormones increase pigment production in the skin, it also darkens the nipples. But this time there's a solid benefit to your body's changes: some scientists theorize that darker nipples are easier for baby to spot -- and that means they can make a beeline for them to breastfeed.

Is It True That Pregnant Women Are More Emotional?

Perhaps, although the usual scapegoat, "pregnancy hormones," may not be the true culprit. Rather, it's just plain old stress of pondering just how much your life will change once the baby arrives. "I believe that emotions can run high if a mom is stressed or anxious, and pregnancy can certainly add to a person's underlying level of stress and worry," says Dr. Ahlering. "This extra amount can show itself with heightened sensitivity and emotion of different sorts, from a short fuse to crying episodes."